I believe that rule is pretty common throughout the ‘snow’ States.
What bedevils me is that the “sidewalk” is public property - so how come any private citizen is responsible to ‘keep it clean’???????
That would be a public access easement on private property.
There are some things a society does to benefit others. Shoveling the walk benefits people from having to walk on the street. Where I live I own the property from my house to the side walk. The green between the sidewalk and the street is not my own yet I cut it to be a good neighbor. How much would it cost to have the surrounding govt come by just to shovel your walk? Can you imagine the regulations they’d crush you with if they were, in fact, in charge of shoveling your walk? No bush or flower pots within 10’, no cars nearby, maybe no shoveling your driveway until the sidewalk’s been done first, it just goes on and on...